Agricultural equipment manufacturers are developing electric and autonomous machines to replace today’s diesel tractors and combines. The sheer everyday demands — running dusk to dawn at planting and harvesting or the tonnage hauled to the elevator — are issues to address as governments demand lower greenhouse gas emissions.
“The critical piece of the pie for greater adoption of electric vehicles in farm settings is charging infrastructure, followed closely by durability and reliability issues,” says Scott Miller, associate dean for industry partnerships at Ohio University’s Russ College of Engineering and Technology. “Farmers will not abide things that they cannot fix quickly, cheaply and easily.”
In addition, diesel offers farmers the ability to work all day.
“Today the reason why most agricultural machinery is [run by] diesel is because of the high power-to-weight ratios when we look at energy storage in the form of diesel fuel,” says Scott Shearer, chair of the Department of Food, Agricultural and Biological Engineering at Ohio State University.
Although diesel power is dominant now, the market for electric vehicles in the construction, agriculture and mining industries could grow to $100 billion annually, according to analysts Peter Harrop and Michael Dent at IDTechEx, headquartered in England.
It’s still unclear precisely what mix of incentives, regulations and market forces might drive the transition to electric farm equipment, but countries will need to address the sector in order to achieve emissions reductions on a scale to avert worst-case climate change scenarios this century.
The Intergovernmental Panel on Climate Change’s report in 2020 underscored the need for immediate steps to cut greenhouse gas emissions. Agriculture accounted for about 5% of U.S. industrial energy consumption last year, according to the Energy Information Administration.
Larger companies that make farm vehicles generally sell to global markets. So developments in other regions will likely affect the range of product offerings worldwide. Mindful of the clean energy transition, multiple companies already have been working on electric-powered prototypes.
John Deere’s model tractors would allow autonomous operation, which increases efficiency and precision. Cable power could even eliminate the need for onboard batteries, meaning an electric version need not weigh more than its fossil-fueled counterpart. Kubota models introduced in 2020 would also allow autonomous operation, and triangular track arrangements could minimize weight and adjust for height in the field. California-based Solectrac already offers 30 and 40-horsepower-equivalent tractors and farm utility vehicles. Other options come from Fendt, Rigitrac, Escorts and others.
“We’re beginning to see some agricultural sprayers that are actually operated with photovoltaics,” Shearer adds. An autonomous weed-control robot from Swiss-based ecoRobotix aims to use 95% less herbicides, for example.
Research also is focusing on small electric ground-based autonomous vehicles. But field navigation could still be tricky because it does no good if the battery runs out in the middle of a 1,000-acre field.
If batteries provide only about 15% of the energy that a full tank of diesel does, Shearer says farmers are still going to have to stop 6 or 7 times a day to swap out batteries. Those stops could cost thousands of dollars during planting.
Adding bigger batteries isn’t the answer either. The additional weight can compact soil more than existing equipment does. The result could be less room for young plants’ roots to grow, says Dale Arnold, director of energy, utility and local government policy for the Ohio Farm Bureau Federation.
Compacted soil also can interfere with no-till methods that many farmers have been using, Arnold adds. No-till farming leaves more organic material and nutrients in the soil. The practice also lets more water infiltrate the soil, resulting in less runoff and nutrient pollution.
“The one key issue is going to be breakthroughs in battery technology,” Shearer says.
In his view, an increase in battery power to half the energy delivered by the equivalent weight of diesel fuel is enough to be “a game-changer.”
Wi-Fi connectivity is an additional challenge. Miller says autonomous navigation and controls, on-board diagnostics, and other devices will depend on good high-speed communications with base stations or the internet.
“As we know, rural broadband is a huge limiting factor for rural communities,” Miller says, “so these sorts of models will take time to implement and may require creative partnerships with major tech companies to overcome these connectivity hurdles.”
A specific time frame for widespread adoption of electric vehicles on farms remains undefined. Climate advocates generally want emission cuts to come sooner, rather than later. And if the world indeed shifts to net-zero greenhouse gas emissions within the next few decades, equipment manufacturers will want to continue to meet farmers’ needs.
"Farmers are interested in tools that will help them increase yields and productivity,” Miller says. “The upside, hopeful note is that these tools have the potential to transform the method and manner in which agricultural producers manage their lands and crops by increasing efficiency and using their limited resources as wisely as possible.”